Ethers

ABSTRACT

There are disclosed 1-[4-(halophenoxy)phenoxy]-4-pentines of formula ##STR1## wherein R 1  and R 2  are each independently of the other chloro or fluoro and one of R 1  and R 2  is also hydrogen, a process for their preparation and intermediates for their preparation, the use of these compounds in pest control, and pesticidal compositions which contains a compound of formula I as active component. The preferred field of use is ovicidal control of pests.

This application is a continuation of application Ser. No. 403,254,filed Sep. 5, 1989, now abandoned.

The present invention relates to 1-[4-(halophenoxy)phenoxy]-4-pentines,to the preparatioin thereof and to intermediates for their preparation,and to the use of these compounds in pest control.

The compounds of this invention have the formula I ##STR2## wherein R₁and R₂ are each independently of the other chlorine or fluorine and oneof R₁ and R₂ can also be hydrogen.

Among the compounds of formula I, the monofluoro and difluoro compoundsas well as the monochloro and dichloro compounds are preferred for usein pest control.

Preferred individual compounds are:

1-[4-(4-fluorophenoxy)phenoxy]-4-pentine,

1-[4-(2-fluorophenoxy)phenoxy]-4-pentine, and

1-[4-(2,4-difluorophenoxy)phenoxy]-4-pentine.

Substituted phenoxy-4-pentines are disclosed as acaricides in U.S.patent specification 2,304,962. However, this reference does not specifyany individual compounds from among the1-[4-(monohalophenoxy)phenoxy]-4-pentines also covered by thedefinition. Finally, German Offenlegungsschrift 2 305 698 disclosessubstituted phenoxy-2-pentines, and German Offenlegungsschrift 2 547 146discloses substituted (4-phenoxyphenoxyalkyl)(alkynyl) ethers andthioethers with acaricidal properties.

These compounds, however, have not proved satisfactory in all respectsas regards their acaricidal and, especially, ovicidal activity.

It is the object of the present invention to provide further acaricideswith improved activity.

Surprisingly, it has been found that the novel compounds of formula Ihave an improved acaricidal, especially ovicidal, activity as comparedwith the compounds of the prior art.

The ovicidal activity of the compounds of formula I against aphids,specifically against Dysaphis plantaginea, Aphis pomi and Dysaphisbrancoi.

The compounds of formula I can be prepared by reacting a4-(halophenoxy)phenolate of formula II, wherein R₁ and R₂ are as definedfor formula I and M is an alkali metal or alkaline earth metal, with a1-halo-4-pentine of formula III, wherein R₃ is chloro, bromo or iodo:##STR3## in an inert solvent and in the temperature range from -10° C.to +140° C.

It is preferred to carry out the process in the presence of an alkalimetal iodide in a polar aprotic solvent, for example dimethyl sulfoxide,sulfolane or a dialkyl amide such as dimethyl formamide, in thetemperature range from 0° to 80° C., and R₃ is chloro.

The present invention also relates to the process for the preparation ofthe compounds of formula I.

The intermediate 4-(2,4-difluorophenoxy)phenol can be prepared byreacting 4-(2,4-difluorophenoxy)anisole with an aqueous hydrohalic acid,preferably 30-50% hydrobromic acid or hydriodic acid, in the temperaturerange from 80°-130° C., preferably from 100°-110° C., and preferably inglacial acetic acid as solvent.

The invention also relates to the novel 4-(2,4-difluorophenoxy)phenoland to the preparation thereof.

The phenolate of formula II can be prepared from the4-(2,4-difluorophenoxy)phenol and a suitable base, for example an alkalimetal hydroxide or alkaline earth metal hydroxide, an alkali metalalcoholate or alkaline earth metal alcoholate, an alkali metal hydrideor alkaline earth metal hydride or, finally, sodium or potassiumcarbonate, by known methods, and, if desired, isolated.

The starting materials of formulae II and III are known and, where theyare novel, can be prepared by known methods.

The compounds of this invention are valuable pesticides while being welltolerated by warm-blooded animals and by plants. The compounds offormula I are therefore suitable e.g. for controlling pests of animalsand plants. Such pests belong principally to the phylum of Arthropoda,such as in particular insects of the orders Lepidoptera, Coleoptera,Homoptera, Heteroptera, Diptera, Thysanoptera, Orthoptera, Anoplura,Siphonaptera, Mallophaga, Thysanura, Isoptera, Psocoptera or Hymenopteraand arachnids of the order Acarina, e.g. mites and ticks, especially thefruit tree red spider mite (Panonychus ulmi), as well as aphids. Everydevelopment stage of the pests can be controlled, i.e. the adults, pupaeand nymphs, and also in particular the larvae and, preferably, the eggs.It is thus possible to control effectively in particular larvae and eggsof phytopathogenic insect pests and mites in crops of ornamentals anduseful plants, for example in vegetable and cotton crops and, inparticular, in fruit crops. The control of preimaginal stages ofphytopathogenic insects is to be singled out for special invention. Ifcompounds of formula I are ingested by imagines, then a direct kill ofthe pests or a reduced oviposition and/or hatching rate can be observed.

For the control of pests that are parasites of animals, especially ofdomestic animals and productive livestock, ectoparasites such as mitesand ticks, and Diptera such as Lucilia sericata, are of particularinterest.

The good pesticidal activity of the compounds of formula I correspondsto a mortality of at least 50-60% of the above pests.

The compounds of this invention are of particular interest forcontrolling fruit tree red spider mites of the genus Panonychus, inparticular of the species Panonychus ulmi.

The conventional method in agricultural practice of controlling thispest, the eggs of which winter in the fruit trees and the firstgeneration of which causes particularly severe damage to fruit crops,comprises spraying ovicidal compositions of the prior art in aconcentration of 50 g/100 l on the cultivated plant before flowerformation and, after this treatment, controlling the pests in the mobiledevelopment stages 2 to 3 weeks later with other suitable pesticides.

In contradistinction thereto, the compounds of this invention, whensprayed in a concentration of only 30 g/100 l before flower formation,afford comprehensive protection against the fruit tree red spider mitefor a period of over six weeks and thus effect almost total kill of thepests.

The compounds of formula I have an exceedingly broad activity. Theirovicidal activity is very pronounced against the fruit tree red spidermite as well as against the rosy apple aphid.

The activity of the compounds of formula I and of the compositionscontaining them can be substantially broadened and adapted to prevailingcircumstances by addition of other insecticides and/or acaricides.Examples of suitable additives include: organophosphorus compounds,nitrophenols and derivatives thereof, formamidines, ureas, carbamates,pyrethroids, chlorinated hydrocarbons, and Bacillus thuringiensispreparations.

The compounds of formula I are used in unmodified form, or preferablytogether with the inert, agriculturally acceptable adjuvantsconventionally employed in the art of formulation, and can therefore beformulated in known manner to emulsifiable concentrates, directlysprayable or dilutable solutions, dilute emulsions, wettable powders,soluble powders, dusts, granulates, and also encapsulations in e.g.polymer substances. As with the compositions, the methods of applicationsuch as spraying, atomising, dusting, scattering or pouring, are chosenin accordance with the intended objectives and the prevailingcircumstances.

The formulations, i.e. the compositions, preparations or mixturescontaining the compound (active ingredient) of formula I or combinationsthereof with other insecticides or acaricides, and, where appropriate, asolid or liquid adjuvant, are prepared in known manner, e.g. byhomogeneously mixing and/or grinding the active ingredients withextenders, e.g. solvents, solid carriers and, in some cases,surface-active compounds (surfactants).

Suitable solvents are: aromatic hydrocarbons, preferably the fractionscontaining 8 to 12 carbon atoms, e.g. xylene mixtures or substitutednaphthalenes, phthalates such as dibutyl phthalate or dioctyl phthalate,aliphatic hydrocarbons such as cyclohexane or paraffins, alcohols andglycols and their ethers and esters, such as ethanol, ethylene glycol,ethylene glycol monomethyl or monoethyl ether, ketones such ascyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone,dimethyl sulfoxide or dimethylformamide, as well as vegetable oils orepoxidised vegetable oils such as epoxidised coconut oil or soybean oil;or water.

The solid carriers used e.g. for dusts and dispersible powders arenormally natural mineral fillers such as calcite, talcum, kaolin,montmorillonite or attapulgite. In order to improve the physicalproperties it is also possible to add highly dispersed silicic acid orhighly dispersed absorbent polymers. Suitable granulated adsorptivecarriers are porous types, for example pumice, broken brick, sepioliteor bentonite; and suitable nonsorbent carriers are materials such ascalcite or sand. In addition, a great number of pregranulated materialsof inorganic or organic nature can be used, e.g. especially dolomite orpulverised plant residues.

Depending on the nature of the compound of formula I to be formulated,or of combinations thereof with other insecticides or acaricides,suitable surface-active compounds are non-ionic, cationic and/or anionicsurfactants having good emulsifying, dispersing and wetting properties.The term "surfactants" will also be understood as comprising mixtures ofsurfactants.

Suitable anionic surfactants can be both water-soluble soaps andwater-soluble synthetic surface-active compounds.

Suitable soaps are the alkali metal salts, alkaline earth metal salts orunsubstituted or substituted ammonium salts of higher fatty acids (C₁₀-C₂₂), e.g. the sodium or potassium salts of oleic or stearic acid, orof natural fatty acid mixtures which can be obtained e.g. from coconutoil or tall oil. Further suitable surfactants are also the fatty acidmethyl taurin salts as well as modified and unmodified phospholipids.

More frequently, however, so-called synthetic surfactants are used,especially fatty sulfonates, fatty sulfates, sulfonated benzimidazolederivatives or alkylarylsulfonates.

The fatty sulfonates or sulfates are usually in the form of alkali metalsalts, alkaline earth metal salts or unsubstituted or substitutedammonium salts and contain a C₈ -C₂₂ alkyl radical which also includesthe alkyl moiety of acyl radicals, e.g. the sodium or calcium salt oflignosulfonic acid, of dodecylsulfate, or of a mixture of fatty alcoholsulfates obtained from natural fatty acids. These compounds alsocomprise the salts of sulfated and sulfonated fatty alcohol/ethyleneoxide adducts. The sulfonated benzimidazole derivatives preferablycontain 2 sulfonic acid groups and one fatty acid radical containing 8to 22 carbon atoms. Examples of alkylarylsulfonates are the sodium,calcium or triethanolamine salts of dodecylbenzenesulfonic acid,dibutylnaphthalenesulfonic acid, or of a condensate ofnaphthalenesulfonic acid and formaldehyde. Also suitable arecorresponding phosphates, e.g. salts of the phosphoric acid ester of anadduct of p-nonylphenol with 4 to 14 moles of ethylene oxide.

Non-ionic surfactants are preferably polyglycol ether derivatives ofaliphatic or cycloaliphatic alcohols, or saturated or unsaturated fattyacids and alkylphenols, said derivatives containing 3 to 30 glycol ethergroups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moietyand 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.

Further suitable non-ionic surfactants are the water-soluble adducts ofpolyethylene oxide with polypropylene glycol,ethylenediaminopolypropylene glycol and alkylpolypropylene glycolcontaining 1 to 10 carbon atoms in the alkyl chain, which adductscontain 20 to 250 ethylene glycol ether groups and 10 to 100 propyleneglycol ether groups. These compounds usually contain 1 to 5 ethyleneglycol units per propylene glycol unit.

Representative examples of non-ionic surfactants arenonylphenolpolyethoxyethanols, castor oil polyglycol ethers, castor oilthioxilate, polypropylene/polyethylene oxide adducts,tributylphenoxypolyethoxyethanol, polyethylene glycol andoctylphenoxypolyethoxyethanol. Fatty acid esters of polyoxyethylenesorbitan, e.g. polyoxyethylene sorbitan trioleate, are also suitablenon-ionic surfactants.

Cationic surfactants are preferably quaternary ammonium salts whichcontain, as N-substituent, at least one C₈ -C₂₂ alkyl radical and, asfurther substituents, unsubstituted or halogenated lower alkyl, benzylor hydroxy-lower alkyl radicals. The salts are preferably in the form ofhalides, methylsulfates or ethylsulfates, e.g. stearyltrimethylammoniumchloride or benzyl bis(2-chloroethyl)ethylammonium bromide.

The surfactants customarily employed in the art of formulation aredescribed e.g. in "McCutcheon's Detergents and Emulsifiers Annual", MCPublishing Corp., Ridgewood, N.J., 1979; Dr. Helmut Stache, "TensidTaschenbuch" (Handbook of Surfactants), Carl Hanser Verlag,Munich/Vienna, 1981.

The pesticidal compositions usually contain 0.1 to 99%, preferably 0.1to 95%, of a compound of formula I or a combination thereof with otherinsecticides or acaricides, 1 to 99.9% of a solid or liquid adjuvant,and 0 to 25%, preferably 0.1 to 20%, of a surfactant.

Whereas commercial products are preferably formulated as concentrates,the end user will normally employ diluted formulations of substantiallylower concentration.

The compositions may also contain further ingredients, such asstabilisers, antifoams, viscosity regulators, binders, tackifiers aswell as fertilisers or other active ingredients for obtaining specialeffects.

EXAMPLES PREPARATION OF THE ACTIVE SUBSTANCES AND OF THE INTERMEDIATESp1: Preparation of 4-(2,4-difluorophenoxy)anisole ##STR4##

To a suspension of the anhydrous sodium salt of 206 g of2,4-difluorophenol in 400 ml of diethylene glycol dimethyl ether areadded 5 g of copper powder, 5 g of copper(I) iodide, 8 ml of pyridineand 393 g of 4-bromoanisole. With stirring, the reaction mixture isheated, under nitrogen, for 17 hours to 150°-155° C. After cooling, thereaction mixture is filtered over Hyflo and the bulk of the solvent isremoved by vacuum distillation. The residue is dissolved in ether andthe ethereal solution is washed repeatedly with 10% aqueous sodiumhydroxide and then with water. The ethereal solution is dried oversodium sulfate and the solvent is removed by distillation. The residueis purified by chromatography over silica gel (eluant: 8:1 mixture ofpetroleum ether/diethyl ether). The solvent is removed by evaporation,to give the title compound in the form of a residual oil; n_(D) ²²=1.5466.

P2: Preparation of 4-(2,4-difluorophenoxy)phenol ##STR5##

With stirring, 170 g of the 4-(2,4-difluorophenoxy)anisole obtainedaccording to Example P1, 500 ml of 48% hydrobromic acid and 400 ml ofglacial acetic acid are heated for 20 hours to ca. 105° C. After workingup, the crude 4-(2,4-difluorophenoxy)phenol is purified bychromatography over silica gel (eluant: 1:4 mixture of diethylether/n-hexane) as well as by subsequent recrystallisation from diethylether/petroleum ether. The purified title compound has a melting pointof 82°-84° C.

P3: Preparation of the active substance1-[4-(2,4-difluorophenoxy)phenoxy]-4-pentine (compound 1 of Table 1)

With cooling, a solution of 4.2 g of potassium tert-butoxide in 20 ml ofanhydrous dimethyl sulfoxide is added to a solution of a 8 g of4-(2,4-difluorophenoxy)phenol in 20 ml of anhydrous dimethyl sulfoxideand 0.3 g of finely powdered potassium iodide. With stirring, a solutionof 4,4 g of 1-chloro-4-pentine in 5 ml of dimethyl sulfoxide is addeddropwise at 10°-15° C. to the above mixture. After 2 hours the reactionmixture is warmed to room temperature (20°-23° C.) and stirred for 24hours at this temperature. The reaction mixture is then poured intoice-water and extracted repeatedly with a 1:2 mixture of diethylether/hexane. The combined organic phases are washed until neutral withcold 10% aqueous sodium hyroxide and then with water and dried oversodium sulfate. The solvent is removed by vacuum distillation and theresidue is further purified by chromatography over silica gel 60(eluant: 1:9 mixture of diethyl ether/n-hexane), affording the pure1-[4-(2,4-difluorophenoxy)-phenoxy]-4-pentine with a refractive indexn_(D) ²² =1.5392.

Further compounds of formula I, for example ##STR6## were prepared inaccordance with the above Examples.

                  TABLE 1                                                         ______________________________________                                        Compound     R.sub.1  R.sub.2 Phys. data                                      ______________________________________                                        1.           F        F       n.sub.D.sup.20 : 1.5392                         2.           H        F       n.sub.D.sup.20 : 1.5505                         3.           F        H       n.sub.D.sup.20 : 1.5530                         4.           H        Cl      m.p.: 37-38° C.                          5.           Cl       H                                                       6.           Cl       Cl      n.sub.D.sup.21 : 1.5785                         7.           Cl       F                                                       8.           F        Cl                                                      ______________________________________                                    

Formulation of compounds of formula I according to Table 1 (throughout,percentages are by weight)

    ______________________________________                                        F1: Emulsifiable concentrates                                                                         a)     b)                                             ______________________________________                                        a compound according to Table 1                                                                       10%    25%                                            calcium dodecylbenzenesulfonate                                                                       --      5%                                            castor oil polyethylene glycol ether                                                                  25%     5%                                            (36 mol of ethylene oxide)                                                    tributylphenol polyethylene gylcol ether                                                              --     --                                             cyclohexanone           --     40%                                            butanol                 15%    --                                             xylene mixture          --     25%                                            ethyl acetate           50%    --                                             ______________________________________                                    

Emulsions of any required concentration can be produced from suchconcentrates by dilution with water.

    ______________________________________                                        F2: Solutions          a)     b)                                              ______________________________________                                        a compound according to Table 1                                                                      10%     5%                                             polyethylene glycol 400                                                                              70%    --                                              N-methyl-2-pyrrolidone 20%    20%                                             epoxidised coconut oil --      1%                                             petroleum distillate (boiling range                                                                  --     74%                                             160-190° C.)                                                           ______________________________________                                    

These solutions are suitable for application in the form of microdrops.

    ______________________________________                                        F3: Granulates       a)      b)                                               ______________________________________                                        a compound according to Table 1                                                                    5%      10%                                              kaolin               94%     --                                               highly dispersed silicic acid                                                                      1%      --                                               attapulgite          --      90%                                              ______________________________________                                    

The active ingredient or ingredients is or are dissolved in methylenechloride, the solution is sprayed onto the carrier, and the solvent issubsequently evaporated off in vacuo.

    ______________________________________                                        F4: Extruder granulates                                                       ______________________________________                                        a compound according to Table 1                                                                         10%                                                 sodium lignosulfonate      2%                                                 carboxymethylcellulose     1%                                                 kaolin                    87%                                                 ______________________________________                                    

The active ingredient or ingredients is or are mixed and ground with theadjuvants, and the mixture is subsequently moistened with water. Themixture is extruded and then dried in a stream of air.

    ______________________________________                                        F5: Coated granulate                                                          ______________________________________                                        a compound according to Table 1                                                                          3%                                                 polyethylene glycol 200    3%                                                 kaolin                    94%                                                 ______________________________________                                    

The finely ground active ingredient is uniformly applied, in a mixer, tothe kaolin moistened with polyethlene glycol. Non-dusty coatedgranulates are obtained in this manner.

    ______________________________________                                        F6: Dusts          a)      b)      c)   d)                                    ______________________________________                                        a compound according to Table 1                                                                  2%      5%       5%   8%                                   highly dispersed silicic acid                                                                    1%      5%      --   --                                    talcum             97%     --      95%  --                                    kaolin             --      90%     --   92%                                   ______________________________________                                    

Ready-for-use dusts are obtained by intimately mixing the carriers withthe active ingredient and, optionally, grinding the mixture in asuitable mill.

    ______________________________________                                        F7: Wettable powders a)      b)       c)                                      ______________________________________                                        a compound according to Table 1                                                                    20%     50%      75%                                     sodium lignosulfonate                                                                              5%       5%      --                                      sodium lauryl sulfate                                                                              3%      --        5%                                     sodium diisobutylnaphthalenesulfonate                                                              --       6%      10%                                     octylphenol polyethylene glycol ether                                                              --       2%      --                                      (7-8 mol of ethylene oxide)                                                   highly dispersed silicic acid                                                                      5%      10%      10%                                     kaolin               67%     27%      --                                      ______________________________________                                    

The active ingredient is thoroughly mixed with the adjuvants and themixture is thoroughly ground in a suitable mill, affording wettablepowders which can be diluted with water to give suspensions of thedesired concentration.

    ______________________________________                                        F8: Suspension concentrate                                                    ______________________________________                                        a compound according to Table 1                                                                         40%                                                 ethylene glycol           10%                                                 nonylphenol polyethylene glycol                                                                         6%                                                  (15 mol of ethylene oxide)                                                    sodium lignosulfonate     10%                                                 carboxymethylcellulose    1%                                                  37% aqueous formaldehyde solution                                                                       0.2%                                                silicone oil in the form of a 75%                                                                       0.8%                                                aqueous emulsion                                                              water                     32%                                                 ______________________________________                                    

The finely ground active ingredient is intimately mixed with theadjuvants, giving a suspension concentrate from which suspensions of anydesired concentration can be obtained by dilution with water.

Biological Tests B1: Action against Aedes aegypti

A concentration of 12.5 ppm is obtained by pipetting a specific amountof a 0.1% solution of the test compound in acetone onto the surface of150 ml of water in a beaker. After the acetone has evaporated, 30 to 40two-day old larvae of Aedes aegypti are put into the beaker containingthe test compound. Mortality counts are made after 2 and 7 days.

Compounds of Table 1 exhibit good activity in this test.

B2: Action against Spodoptera littoralis and Heliothis virescens (larvaeand eggs)

Three cotton plants each having a height of about 15-20 cm and grown inpots are treated with a sprayable liquid formulation of the testcompound. After the spray coating has dried, the potted plants areplaced in a metal container having a capacity of about 20 liters andcovered with a glass plate. The humidity in the interior of the coveredcontainer is regulated such that no water of condensation forms. Directlight falling on the plants is avoided. The three plants are theninfested altogether with:

a) 50 larvae of Spodoptera littoralis or Heliothis virescens in the L₁-stage;

b) 20 larvae of Spodoptera littoralis or Heliothis virescens in the L₃-stage;

c) 2 egg deposits of Spodoptera littoralis or Heliothis virescens. (Theprocedure is that two leaves of each plant are put into a plexiglasscylinder sealed at both ends with gauze. Two egg deposits of Spodoptera,or a part of a cotton leaf with eggs of Heliothis deposited thereon, areadded to the leaves sealed in the cylinder.)

Evaluation in comparison with untreated controls is made after 4 to 5days on the basis of the following criteria:

a) the number of still living larvae,

b) inhibition of larval development and moulting,

c) feeding damage (shredding and perforation damage),

d) hatching rate (number of larvae hatched from the eggs).

In this test, compounds of Table 1 exhibit good overall activity at aconcentration of 400 ppm.

B3: Ovicidal action against Spodoptera littoralis

Eggs of Spodoptera littoralis deposited on filter paper are cut out ofthe paper and immersed in a 0.05% by weight solution of the testcompound in a 1:1 mixture of acetone-water. The treated egg deposits arethen removed from this mixture and kept in plastic dishes at 28° C. and60% relative humidity. The hatching rate, i.e. the number of larvaewhich have developed from the treated eggs, is determined after 5 days.

Compounds of Table 1 exhibit good activity in this test.

B4: Action against Laspeyresia pomonella (eggs)

Egg deposits of Laspeyresia pomonella not more than 24 hours old areimmersed on filter paper for 1 minute in an aqueous acetonic solutioncontaining 400 ppm of the test compound.

After the solution has dried, the filter paper and the eggs are placedin petri dishes and kept at a temperature of 28° C. The percentage oflarvae hatched from the treated eggs is evaluated after 6 days.

Compounds of Table 1 exhibit good activity in this test.

B5: Ovicidal action against Heliothis virescens and Spodopteralittoralis

Appropriate amounts of a wettable powder formulation containing 25% byweight of the test compound are mixed with sufficient water to producean aqueous emulsion with an active ingredient concentration of 400 ppm.One-day-old egg deposits of Heliothis on cellophane and of Spodoptera onpaper are immersed in these emulsions for 3 minutes and then collectedby suction on round filters. The treated deposits are placed in petridishes and kept in the dark at 28° C. and 60% relative humidity. Thehatching rate, i.e. the number of larvae which have developed from thetreated eggs, in comparison with untreated controls, is determined after5 to 8 days.

In this test, compounds of Table 1 exhibit an 80 to 100% ovicidalactivity (mortality) against Heliothis virescens and Spodopteralittoralis.

B6: Comparison of the compounds of the invention with those of the priorart with respect to ovicidal action against Panonychus ulmi

Compounds 1, 2 and 3 are tested with the following comparison compoundsof the prior art.

    __________________________________________________________________________    Compound                                                                            Formula                   Reference                                     __________________________________________________________________________           ##STR7##                 DE-OS 2 304 962                               B                                                                                    ##STR8##                 DE-OS 2 305 698                               C                                                                                    ##STR9##                 DE-OS 2 305 698                               __________________________________________________________________________

Method of determining the ovicidal action against Panonychus ulmi

Discs measuring 5 cm in diameter are punched from apple leaves. Thesediscs are laid on moist cotton wool in a plastic petri dish. Then 7adult females of Panonychus ulmi are placed on each disc and left for 48hours for oviposition. Application of the test compounds is made afterremoval of the females. The discs are sprayed with a hand atomizer untila fine coating of droplets has formed on them. Two dishes are treatedwith each test compound at concentrations of 50 and 25 mg of activesubstance per liter. After the spray coatings have dried, the dishes arecovered, kept at 25° C. and, 6 days after application, the percentage ofnon-hatched eggs is determined (ovicidal action). Three replicates arecarried out at intervals of 4 weeks.

Comparison of ovicidal action:

                  TABLE 2                                                         ______________________________________                                                        Conc.   Ovicidal action                                       Active compound mg/1    in %                                                  ______________________________________                                        A (prior art)   50      72                                                                    25      61                                                    B (prior art)   50      67                                                                    25      32                                                    C (prior art)   50      71                                                                    25      43                                                    1 (Table 1)     50      100                                                                   25      98                                                    2 (Table 1)     50      88                                                                    25      67                                                    3 (Table 1)     50      93                                                                    25      78                                                    ______________________________________                                         B7: Action against the eggs of Dysaphis plantaginea and of Dysaphis     brancoi in a field test

Winter eggs of Dysaphis plantaginea and Dysaphis brancoi (roses appleaphids) are sprayed with a spray mixture containing 30 g of activecompound per 100 l in the open.

Evaluation of hatched and developing aphids is made one month after thisapplication, based on the total number of eggs. The percentage ofhatched and developing aphids determined after treatment with compounds1, 2 and 3 at a uniform rate of application of 450 g/ha is:

Dysaphis plantaginea=10%

Dysaphis brancoi=4%

B8: Action against eggs of Aphis pomi (green apple aphid) in alaboratory test

Pieces of apple branch 10 cm long (2-year-old wood from winter pruning)which are infested with winter eggs of A. pomi are immersed for 1 minutein a spray mixture of test compound containing 30 g of active substanceper 100 l. The treated pieces are kept for 4 weeks in air-permeable testcontainers at 22° C. and 60-80% relative humidity. The hatching rate ofthe treated eggs is determined by examination under a stereoscopicmicroscope. Compounds 1, 2 and 3 effect an ovicidal action of >80%against Aphis pomi.

What is claimed is:
 1. A 1-[4-(halophenoxy)phenoxy]-4-pentine of formulaI ##STR10## wherein R₁ and R₂ are each independently of the otherhydrogen or fluoro with the proviso that R₁ and R₂ are notsimultaneously hydrogen.
 2. A 1-[4-(4-fluorophenoxy)phenoxy]-4-pentineaccording to claim
 1. 3. A 1-[4-(2-fluorophenoxy)phenoxy]-4-pentineaccording to claim
 1. 4. A 1-[4-(2,4-difluorophenoxy)phenoxy]-4-pentineaccording to claim
 1. 5. A pesticidal composition which comprises aneffective amount of a 1-[4-(halophenoxy)phenoxy]-4-pentine or mixture of1-[4-(halophenoxy)phenoxy]-4-pentines of formula I ##STR11## wherein R₁and R₂ are each independently of the other hydrogen or fluoro with theproviso that R₁ and R₂ are not simultaneously hydrogen.
 6. A pesticidalcomposition according to claim 5, which comprises1-[4-(4-fluorophenoxy)phenoxy]-4-pentine.
 7. A pesticidal compositionaccording to claim 5, which comprises1-[4-(2-fluorophenoxy)phenoxy]-4-pentine.
 8. A pesticidal compositionaccording to claim 5, which comprises1-[4-(2,4-difluorophenoxy)phenoxy]-4-pentine.